John o



(No Model.)

J. 0. OHEBVER.

ROTARY PUMP.

No. 349,270. Patented Sept. 14, 1886.

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UNITED STATES PATENT OFFICE.

JOHN O. GHEEVER, OF BOSTON, MASSACHUSETTS, ASSIGNOR TO HIMSELF AND HENRYT. LITOHFIELD, OF SAME PLACE.

ROTARY PUM P.

SPECIFICATION forming part of Letters Patent No. 349,270, datedSeptember 14, 1886. Application filed January 27, 1886. Serial No.189,988. (No model.)

To all whom, it may concern.-

Be it known that I, JOHN O. 'GHEEVER, a citizen of the United States,residing at Boston, in the county of Suffolk and State of Massachusetts,have invented a new and useful Improvement in Rotary Pumps, of which-thefollowing is a specification.

My invention relates to an improvement in rotary pumps of that class inwhich two ro- IO tating cams or disks are employed, and which areprovided each, respectively, with projections and cavities fitting onewithin the other as the cams or disks rotate.

My invention consists of two cylinders or pistons, each having twoprojections and two corresponding cavities, which engage each with theother as the pistons rotate. The projections are made hollow and arecast with the pistons, and after being cast a slit is made in theprojections at one side and at a point contiguous to the periphery ofthe piston, for the purpose of allowing the projection to expand to makea tight packing, and also to compensate for the wear of the casing.

Referring to the accompanying drawings, Figure 1 is ,a side view showingthe means for driving the pistons. Fig. 2 is a plan or top view. Fig. 3is a section of the casing and pistons, and Fig. 4 is a side view of oneof the pistons on an enlarged scale.

A represents the casing in which the pistons revolve, and it is providedwith flanges a a. on each side, to which the heads A are secured. Thecasing A is also provided with openings 5 on its upper and lower sides,which form the inlet and outlet F and G, and also with flanges a, forsecuring it in position. The heads A are provided with ordinary stuflingboxes, through which the shafts J pass. On the shafts 0 J are mountedcylinders or pistons E E, each having two projections, 6, and twocorrespond ing cavities, g, so arranged that as the pistons E revolvethe projections on one piston will fit into the cavity on the otherpiston. The projections c are cast in one with the piston E, 5 and theirouter surface is a segment of a circle. An aperture, 0, is drilled orotherwise formed half in the piston and half in the projection e, sothat the thickness of the projection is greater on one side than theother. A slit is cut on the thinnest side of the projection at a pointcontiguous to the periphery of the piston E, so as to leave theprojection attached to the piston at the thickest side only, and therebyact as a spring. they revolve the pressure of the fluid will be on thethinnest side of the projection e, and will be forced through the slitinto the aperture 6, and force the projection 6 so as to be in contactwith the inner side of the casing or cylin- 6o der A, thereby insuring aperfect vacuum and compensating for any wear. The pistons are to bedriven by any suitable power.

What I claim as my invention is 1.v I11 a rotary pump, the pistons E E,each provided with projections e e and apertures e 0, so arranged thateach projection will be thicker on one side than the other, and thethinnest side being separated from the piston, so that it will act as aspring, in combination with recesses g g, substantially as shown, andfor the purposes described.

2. In a rotary pump, the pistons E E, pro vided with semicircular springprojections e, in combination with corresponding cavities, g, 7 5substantially as shown, and for the purposes described. I In testimonywhereof I have signed my name to this specification in the presence oftwo subscribing witnesses.

JOHN O. OHEEVER. Witnesses:

J. H. AnAMs, E. PLANTA.

The pistons are so set that as 55

